Three centuries in the future mankind knows peace and technological perfection, however one man is not happy with the state of the peaceful world. This man is the mad scientist known as Zarrko, who has built a time machine to travel into the past in the hopes of procuring humanities powerful atomic weapons so that he might use them to conquer his future.

In the present day, Thor has agreed to aid the US Military in missile tests, flying along with test missiles to review their efficiency. Hoping to test the effects of their new Cobalt bomb on human beings by studying how it effects Thor, the army has the Thunder God strapped to measuring devices and have him stand in close proximity of this new experimental bomb. However, the test does not go as planned, as Zarrko appears in his time machine and pilfers the device and escapes into the future before Thor can stop him.

Part 2: Flight to the Future

Promising to recover the bomb, Thor summons his father Odin and asks how he might travel into the future. Odin guides him to using his hammer to time travel by tying a fragment of Zarrko's craft (broken off in the brief battle between Thor and Zarrko) and spin his hammer faster than the speed of light and it's magic will transport him to the future. The spell works and Thor is sent into the future year of 2262, where he finds that Zarrko has used the C-Bomb to take over the future Earth.

When Zarrko learns of Thor's arrival in his time, he sends his newly established guards after Thor. Thor quickly finds someone from the future to act as a decoy, putting on a costume like Thor, while Thor dons a black robe and the two storm Zarrko's citadel. Inside, the fake Thor is captured lulling Zarrko into a false sense of security when he is suddenly ambushed by the real Thor. When Zarrko's weapons fail he flees and sics an army of robots against Thor, who grab his hammer.
Using a water pipe to short circuit the robots, Thor manages to make them drop his hammer before the sixty second time limit would have him change back into Donald Blake.

Zarrko meanwhile has escaped in a ship and is planning to drop the C-Bomb on the city, however Thor summons up a storm which causes Zarrko's ship to fly erratically enough for Thor to recover the dropped bomb. When Zarrko's ship crashes, the villain survives but has suffered amnesia and is taken into custody. Praised as a hero, Thor then returns to the present where he returns the C-Bomb back to the military.

Later, back in his guise of Donald Blake, Thor returns to his office where he finds Jane Foster marveling over the stories about Thor's recent escapade.